Research has shown that applying reduced pressure to a tissue wound may provide several beneficial effects. For example, applying sub-atmospheric pressure to a wound may lead to retraction of the damaged tissue edges and thus may expedite healing by facilitating wound contraction. Reduced pressure wound therapy may also provide mechanical stimulation to the damaged tissue, which may release growth factors to the wound bed to promote healing. In some cases, applying suction to a wound may remove necrotic tissue from the wound bed and may help to reduce bacterial load.
In the delivery of reduced pressure wound therapy, an airtight dressing is applied to a part of the body having a wound and a certain negative pressure is introduced to the wound area. It is desirable to maintain a substantially constant level of reduced pressure to the wound site. In such therapy, factors such as air leaks and fluid ingress contribute to the overall decrease in the magnitude of the reduced pressure; thus the reduced pressure tends to move towards atmospheric pressure. Except with the use of vacuum bottles, the source of the substantially constant reduced pressure may include some mechanism to compensate for the leaks or fluid ingress in order to maintain the pre-set negative pressure of the system. Examples of negative pressure sources that accomplish this are regulated by an electrically-powered pump, a pressure sensing means and a controller means to adjust the output of the pump. However, these systems require an electrical source, are bulky, noisy, and limit patient mobility.
In light of these and other benefits of reduced pressure tissue therapy, methods and devices that ensure a reliable application of reduced pressure to a wound may be desirable.